I think people are missing the the finer points here: this wasn't actually NTR so far, if you go by the correct definition. He never was her BF and she wasn't secretly fckin around or cheating on him. She was open about being a slut and he knew what he was dealing with, what made the story endurable - that and the clear hints that she's actually a deeply broken person that might get healed by genuine affection.
In turn it is also retarded of those who know scream " it's NTR and it should be, don't complain" because it heavily marketed as an " I can fix" her, as people call it ( tho it sounds kinda idiotic). Now if she were to fall back into old habits then the story is dead and it's basically just a another trashy hentai. Hence why people being upset makes sense, though I think it's obvious the MC is actually gonna prevent her from making that mistake.
Short answer: chill, it's really too early to scream "dropped" especially since it is this manga after all.
You are kinda almost right about some things and I do agree with some statements here but you are missing some points yourself: the NTR -definition- is clear, no doubt but language changes and the term NTR is a bit more than "couple and most often woman gets stolen physically and mentally". There is nuances and there is NTR like this here in the sense that we, the readers and MC who people relate to the most and who is the main pov of the story create a bond with a certain character.
"She wasn't secretly fucking around or cheating" well, yeah. Everyone knew she is open for any dude at any time. This incident is something entirely different, tho. It is happening right after major plot (confession) and progress. It is stupidly forced but whatever, that is a different problem. It just does not fit her character and what the manga has been at all and it feels more like NTR than any other happening thus far.
Also,
this is not marketed as an "I can fix her", lol. People screaming "It is NTR and should be!" aren't retarded. They are
misguided by the belief that this is going to be an exact copy of the finished (I think) original NTR-hentai. But it simply isn't even trying to sell as "I can fix her"- almost all hentai-to-mainstream manga are marketed as such; hentai that is released as a manga toning down on the hentai aspects but still going for the same story. It is the exact same as Mizuryuu Kei's "luvslave", NTR hentai that is toned down and released in a normal magazine, same as "Karami Zakari", a heavy NTR hentai/story that was changed (extremely weird, offputting design choices...) to be released in a mag catering towards younger readers.
Big hentai artists/authors are sadly chasing this trend lately of almost only releasing NTR stories in a format fit for mainstream magazines, being read by teens and young adults. I do think it is morally questionable but they never pretend that their manga is something it isn't. It is straight up porn in nicer clothes.
Also, people can complain about this chapter all they want, you should chill. It clearly is a bit out of left field and not the best writing wise. Not every story is 100% perfect, true but they can decide themselves if they want to drop this.
